Would like possibility to transpose white balance to recurring non-white object under changing lightning conditions.
We all know the situation : Took first couple of pictures with a grey card - and colors in those shots are perfect. Then the subject moves to a different lightning condition and you take a next shot of the subject - but the colors in that next shot are off because of those different lightning conditions.

It would be really cool if I can mark objects in the first shot that reoccur in other shots to allow me to use different objects for transposing white balance without the need for grey card shots.
For example : On calibrated shot - you pick some calibration objects (dress / shoes / earrings / etc ...) and store those in a "white balance custom calibration profile". On a latter picture you select the white balance calibration setting and point back to the dress, shoes, earrings (linking up the settings with the new picture)... With that information lightroom should be able to do the magic required to determine the best white balance settings for the second picture that will bring the colors back like it was taken in the first picture.
While it may not be ideal for every occasion - I'm sure it will get a long way ...

Other examples are : You take shot of a swimmer in a swimming pool (known for very complex lightning situations) - The swimming pool is tiled with exactly the same blueish tiles, the pool border is broken white. You now only have to take two calibration shots with grey card of the tiles and the border and all you have to do in future shots is to select the calibration profile "pool" and point it to the border and the tiles ... and done. Whenever other pictures are taken in this same pool - the profile can be reused.

Sounds like a very simple but very cool/powerful feature - haven't found a single tool that allows me to create color calibration profiles like this to transpose white balance so it is possible to get every shot right - without having to continuously use grey cards.